On 1 September 1939, II (Schlacht)/LG 2 led the air assault on Poland, marking the beginning of World War II. The Hs 123 aircraft, equipped with 50-kg bombs on wing racks and MG 17 guns, flew just above Polish cavalry brigades for ten days. The terrifying noise of the BMW radial engine proved as effective at dispersing mounted columns as the bombs. The Hs 123’s effectiveness in the Polish campaign led to the reversal of plans to re-equip II (Schlacht)/LG 2.
The next target for the unit was Belgium, where they supported the 6th Army in its offensive starting 10 May 1940. They initially engaged Belgian sappers trying to destroy bridge crossings over the Albert Canal. Advancing through Luxembourg and the Ardennes, the Hs 123s reached France and by 21 May, were the most forward-based Luftwaffe unit at Cambrai. After the victory in France, II (Schlacht)/LG 2 returned to Germany to re-equip with the Bf 109E. However, due to the Hs 123’s legendary ability to absorb battle damage, the unit only partially transitioned to the Messerschmitt fighter.
In April 1941, after operations in the Balkans, the unit joined the southern front in the fight against the Soviet Union. It became part of the newly-formed Schlachtgeschwader 1, where the Hs 123 again proved its effectiveness in close support roles. Armed with either four SC 50 bombs, twin 20-mm MG FF cannons, or containers with 92 SC 2 anti-personnel bombs under the wings, and with a centerline fuel tank, the Hs 123 was so dependable that calls for its reinstatement into production were made as late as 1943. The aircraft could take off from quagmire-like fields when other planes could not, provided their wheel spats were removed.
Despite its effectiveness, the Hs 123 faced attrition due to the lack of new production aircraft, leading to its gradual phase-out. By mid-1944, the remaining Hs 123s were grouped in II/Schlachtgeschwader 2.